title: Auditory magnetic mismatch field latency: a biomarker for language impairment in autism.
abstract: BACKGROUND
  Auditory processing abnormalities are frequently observed in autism spectrum disorders (ASD), and these abnormalities may have sequelae in terms of clinical language impairment (LI). The present study assessed associations between language impairment and the amplitude and latency of the superior temporal gyrus magnetic mismatch field (MMF) in response to changes in an auditory stream of tones or vowels.
  
  
  METHODS
  Fifty-one children with ASD, and 27 neurotypical control subjects, all aged 6 to 15 years, underwent neuropsychological evaluation, including tests of language function, as well as magnetoencephalographic recording during presentation of tones and vowels. The MMF was identified in the difference waveform obtained from subtraction of responses to standard from deviant stimuli.
  
  
  RESULTS
  Magnetic mismatch field latency was significantly prolonged (p < .001) in children with ASD, compared with neurotypical control subjects. Furthermore, this delay was most pronounced (∼50 msec) in children with concomitant LI, with significant differences in latency between children with ASD with LI and those without (p < .01). Receiver operator characteristic analysis indicated a sensitivity of 82.4% and specificity of 71.2% for diagnosing LI based on MMF latency.
  
  
  CONCLUSIONS
  Neural correlates of auditory change detection (the MMF) are significantly delayed in children with ASD, and especially those with concomitant LI, suggesting a neurobiological basis as well as a clinical biomarker for LI in ASD.
authors.affiliation: Lurie Family Foundations' MEG Imaging Center, Department of Radiology, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA. robertstim@email.chop.edu
authors.forename: Timothy P L
authors.initials: TP
authors.lastname: Roberts
authors.forename: Katelyn M
authors.initials: KM
authors.lastname: Cannon
authors.forename: Kambiz
authors.initials: K
authors.lastname: Tavabi
authors.forename: Lisa
authors.initials: L
authors.lastname: Blaskey
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Khan
authors.forename: Justin F
authors.initials: JF
authors.lastname: Monroe
authors.forename: Saba
authors.initials: S
authors.lastname: Qasmieh
authors.forename: Susan E
authors.initials: SE
authors.lastname: Levy
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Edgar
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D001303:Auditory Cortex / Q000503:physiopathology*; D001321:Autistic Disorder / Q000150:complications* / Q000503:physiopathology; D002648:Child; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D007806:Language Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D007807:Language Tests; D015225:Magnetoencephalography; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology